In a previous article, we examined how the use of pesticides, fertilisers and wastewater irrigation for agriculture results in soil pollution. In today’s article, we will focus on the use of plastic in agriculture and its impacts on our environment.

In 2019, the European Union alone used over 300,000 tonnes of plastic in Crop production (FAO, n.d.). This represents a significant source of soil pollution and secondary pollution when the plastic is eventually disposed of/burned.

One of the most common sources of plastic in Agriculture is Mulching films. In 2011, it was estimated that over 20 million hectares of farmland in China is covered with plastic film (FAO, n.d.). Mulch Films are plastic sheets used to cover the soil to prevent contamination of the crops and to protect the soil from atmospheric agents, drying and temperature fluctuations (Sotrafa, 2021). Using mulch is found to increase crop yields by 30% since it protects seedlings by limiting evaporation, reducing weed and pest pressures (BBC, n.d.).

Figure 1: Mulch Film covering soil (Sotrafa, 2021)

Another major group of plastics used in Agriculture is Greenhouse Film and Protective Netting. In many countries, greenhouses are used to regulate temperature and precipitation to ensure the continuous growth of crops throughout the year. However, in many developing countries, plastic films and nettings are used as insulators instead of glass due to their comparatively lower cost (FAO, n.d.). These plastic films and nettings will degrade after multiple harvests, requiring more plastic for replacement.

Figure 2: Plastic Greenhouse
Source: https://www.thedailygardener.com/best-greenhouse-plastic

In addition, Agriculture produces numerous other plastic waste such as seedling trays, pesticides containers, irrigation tubing and seed packing. 

The plastic used in farms are contaminated with soil, pesticides and fertilisers making it extremely costly and inefficient to recycle, leaving only burning and burial as the main form of disposal (BBC, n.d.). Most plastics are also non-biodegradable and will over time break down into smaller particles, microplastics. The microplastics can then be ingested by organisms and be passed up the food chain (FAO, n.d.). Furthermore, plastic pollution negatively affects plant growth by altering the activity of soil microorganisms, soil structure and root development (FAO, n.d.).

Today’s article has covered how maximising agriculture yield can produce large quantities of plastic pollution and waste. Do you think we should sacrifice some crop yield to reduce plastic pollution?  Thank you for reading this week’s post. Hope you have a great week ahead.

References

BBC (n.d.). Why food’s plastic problem is bigger than we realise. Retrieved on March 09, 2022 from https://www.bbc.com/future/bespoke/follow-the-food/why-foods-plastic-problem-is-bigger-than-we-realise.html

FAO. (n.d.). Chapter 3: Sources of Soil Pollution. Retrieved on March 09, 2022 from https://www.fao.org/3/cb4894en/online/src/html/chapter-03-3.html

Sotrafa. (2021). What is a mulch film?. Retrieved on March 09, 2022 from https://sotrafa.com/en/what-is-mulching-film/#:~:text=Mulching%20is%20an%20agricultural%20technique,is%20necessary%20for%20vegetative%20development.

Featured Image from https://www.bbc.com/future/bespoke/follow-the-food/why-foods-plastic-problem-is-bigger-than-we-realise.html

As I was researching more about how Agriculture practices pollute the Air, Water and Land, I stumbled upon an interesting article by the Food and Agriculture Organisation (FAO). The article is extremely detailed and complex, describing a wide variety of causes and impacts of soil pollution due to agriculture activities. In this blog post, I will summarise some of the key findings and observations but do consider reading the full article at Sources of Soil Pollution.

According to FAO (n.d.),  agricultural activities pollute soils through (1) Pesticides,(2) Fertilisers, (3)Wastewater for Irrigation, (4) Plastic Materials and (5) Rural Waste). This post will discuss the first 3 types of pollution.

Pesticides

Pesticides are chemical or biological ingredients used by farmers to repel, destroy pests or regulate plant growth. With the rising global demand for food, more pesticides are being used to support more intense agriculture practices. The global usage of pesticide per unit cropland has increased from 1.9 kg/ha in 1990 to 3.3 kg/ha in 2016.

Based on Image 1 below, the Asia region has used the largest amount of pesticides annually.

Image 1: Annual Pesticide usage by region (Source: FAO, n.d.)

While the use of pesticides may help to improve crop yield, they have adverse side effects. Pesticides have long half-lives and can accumulate in the soils and water bodies (if washed into water), causing acute conditions in other organisms. Furthermore, pesticides can be vapourised and transported and deposited beyond the original farmland. Some pesticides also contain trace elements like arsenic, copper and manganese that can be extremely toxic to humans and other animals.

Fertilisers

In order to meet global demand for food, organic fertilizers (e.g. manure, compost) and mineral fertilizers (e.g. Nitrogen, Phosphate) had been used to provide additional nutrients to support crop growth. From 1961 to 2002, the worldwide use of nitrogen (N) fertilization and phosphorus (P) fertilization expanded 7.4-fold and 2.3-fold respectively.

Similar to pesticides, while fertilisers help to improve soil quality and improve crop growth, they do have significant downsides. For instance, the excessive use of nitrogen fertilisers produces nitrous oxide (a greenhouse gas), contributes to soil acidification and eutrophication in nearby water bodies. Even the use of organic fertilisers like animal manure is found to increase antimicrobial resistance in the soil (farmed animals are feed antimicrobial) and increased trace elements like chromium, lead and other toxic metals (minerals are fed to farm animals).

Wastewater for Irrigation 

Wastewater has been widely used in developing countries to irrigate, especially for those farms located in or close to cities. This provides urban or peri-urban farms with low-cost resources for irrigation and the organic materials in wastewater minimise the need for artificial fertilisers. As shown in Figure 2, Mexico uses the largest amount of untreated wastewater for irrigation in the world.

Image 2: Countries that use untreated wastewater for irrigation (Source: FAO, n.d.)

However, the use of non-treated or limited treatment wastewater poses a significant risk. Irrigating with untreated wastewater can contribute to the accumulation of trace elements (e.g. lead), organic contaminants and dangerous pathogens in the edible parts of crops. By consuming these crops, humans can develop severe conditions and diseases.

Conclusion: This blog post has demonstrated that the excessive use of fertilisers, pesticides and wastewater for agriculture can result in immense soil pollution with far-reaching impacts. Do check out the original article by FAO for more details. Hope you have a great week and stay tuned for more articles on pollution from food.

References

FAO. (n.d.). Chapter 3: Sources of Soil Pollution. Retrieved on February 25, 2022 from https://www.fao.org/3/cb4894en/online/src/html/chapter-03-3.html

Feature Image : https://www.deccanherald.com/specials/insight/farmers-consumers-and-ecology-fall-prey-to-pesticides-774954.html

Milk, a relatively inexpensive, calcium-rich and protein-laden super beverage that many of us love and enjoy. In Singapore, a litre of milk will set us back around $3 but can last for 2-3 days.  While Milk is relatively affordable to consumers, the pollution generated from dairying is far from affordable. In today’s blog post, we will examine the pollution and environmental impacts arising from producing milk.

Over the last 3 decades, global Milk production has increased by 59%, from 530 million tonnes in 1988 to 843 million tonnes in 2018 (FAO, 2022). This rapid increase in production has also increased the land, water and air pollution associated with dairying.

Firstly, industrial-scale rearing of Cows for milk produces a large amount of faeces and manure. Furthermore, each dairy cow is estimated to excrete faecal bacteria equivalent to 14 people ( Foot, Joy & Death, 2015). This toxic waste will then seep into groundwater or be washed into nearby water bodies, causing water contamination, excess nutrients and sedimentation (Foote, Joy & Death, 2015). Humans who consumed this contaminated water will suffer from waterborne gastrointestinal diseases and livestock will have affected the growth and mortality.

Next,  the fertilisers used in the grazing fields and cattle urine produces a large amount of Nitrogen. According to a study in New Zealand, nitrogen leaching from dairy land is triple of agricultural land, at an estimated average of 28kg N/ha/year (Foote, Joy & Death, 2015). This results in nitrogen being introduced to water bodies and groundwater, which can lead to certain types of cancers and methemoglobinemia (blood disease) when consumed (Foote, Joy & Death, 2015).  Furthermore, excess levels of nitrogen can cause algae blooms and over-growth of aquatic weeds, resulting in eutrophication (Foote, Joy & Death, 2015)

Figure 1: Algae bloom in Dianchi Lake (Yunnan) due to animal waste 

Apart from water pollution, Dairy produces large quantities of air pollution. The dairy industry alone produces a quarter of New Zealand’s Greenhouse Gase pollution (Foote, Joy & Death, 2015).  Methane is produced by the digestive process of ruminant animals (e.g. Cows) and animal waste while Nitrous oxide is produced from dung, urine and fertilisers used.

Hope you have enjoyed today’s post and learned something. The next time you purchase a cartoon of milk, just remember that it isn’t as cheap or “green” as the packaging might suggest.

References:

FAO. (2022). Milk Production. Retrieved on Feburary 23, 2022 from https://www.fao.org/dairy-production-products/production/en/#:~:text=In%20the%20last%20three%20decades,%2C%20China%2C%20Pakistan%20and%20Brazil.

Foote, K. J., Joy, M. K., & Death, R. G. (2015). New zealand dairy farming: Milking our environment for all its worth. Environmental Management (New York), 56(3), 709-720. https://doi.org/10.1007/s00267-015-0517-x

Featured image from https://unsplash.com/photos/N_vt0wo7OGU

 

In 2015, Singapore experienced an extreme haze event with PM2.5 levels reaching 471 (Today Online, 2015A), forcing schools and outdoor activities to be halted. In Singapore, most of us are familiar with haze given that it is almost an annual event. However, did you know that this immensely pollutive event is due to the production of food products? To be more specific, the production of palm oil.

Haze can be defined as “the existence of dry particles and smoke in the atmosphere when relative humidity is considered lower than usual (<80%) and visibility is below 10km” (Latif et al., 2018). This extreme pollution event is largely caused by slash-and-burn practices or the burning of peatland in Indonesia to provide more land for agriculture (Latif et al., 2018).

Subsequently, the smoke and particulate matter from the burning events in Indonesia are then transported over to Malaysia and Singapore by surface wind (see Figure 1). During the 2015 event, it can be seen that most parts of Malaysia have unhealthy air quality with the Air Pollutant Index (API) ranging from 100-250. The API reflects the average concentration of harmful pollutants like  Sulphur dioxide, Particulate Matter <10 microns, Nitrogen dioxide, Carbon Monoxide and others.

Figure 1: Spreading of Air Pollutants from Indonesia fire to Malaysia and Singapore

(Source: Today Online, 2015B)

Apart from causing discomforts and inconveniences, haze has serious impacts on human health. The particulate matter in Haze is found to contribute to mortality and respiratory illness as the fine particulates can easily enter the respiratory system through inhalation (Latif et al., 2018). A study by Harvard University found that the Indonesia 2015 Haze crisis have been estimated to cause more than 100,000 premature deaths across Indonesia, Malaysia and Singapore (Greenpeace, 2019).

Therefore, this blog post has made it clear that agriculture can be extremely pollutive. Even before the crop is planted, the clearing of forest or existing farmland can produce already produce a large amount of transboundary air pollution. Hence, any legitimate attempts to reduce the pollution of the agriculture industry will need to start at the land acquisition stage.

 

References:

Greenpeace (2019). Asean Haze 2019: The Battle of Liability. Retrieved Feburary 13,2022 from https://www.greenpeace.org/southeastasia/press/3221/asean-haze-2019-the-battle-of-liability/

Latif, M. T., Othman, M., Idris, N., Juneng, L., Abdullah, A. M., Hamzah, W. P., Khan, M. F., Nik Sulaiman, N. M., Jewaratnam, J., Aghamohammadi, N., Sahani, M., Xiang, C. J., Ahamad, F., Amil, N., Darus, M., Varkkey, H., Tangang, F., & Jaafar, A. B. (2018). Impact of regional haze towards air quality in malaysia: A review. Atmospheric Environment (1994), 177, 28-44. https://doi.org/10.1016/j.atmosenv.2018.01.002

Today Online (2015A). PM2.5 levels hit 471 as haze situation worsens. Retrieved February 13, 2022 from https://www.todayonline.com/world/asia/pm25-levels-hit-471-haze-situation-worsens

Today Online (2015B). Mapping the haze in South-east Asia. Retrieved February 13, 2022 from https://www.todayonline.com/world/asia/mapping-haze-south-east-asia

Feature image from https://www.rainforest-alliance.org/wp-content/uploads/2021/07/deforestation-header_0.jpg.optimal.jpg